The use of fiber inclusions to strengthen a matrix is well known to the art. Well established mechanisms for the strengthening of a matrix include slowing and elongating the path of crack propagation through the matrix, as well as energy distribution associated with pulling a fiber free from the surrounding matrix material. In the context of sheet molding composition (SMC) formulations, bulk molding composition (BMC) formulations, and resin transfer molding (RTM) fiber strengthening has traditionally involved usage of chopped glass fibers. There is a growing appreciation in the field of molding compositions that replacing in part, or all of the glass fiber in molding compositions with carbon fiber can provide improved component properties; however, technical problems remain that include disparate layer joinder, fiber flow, fiber surface energies, and surface quality of the resultant component.
The use of carbon fibers in composites, sheet molding compositions, and resin transfer molding (RTM) results in formed components with a lower weight as compared to glass fiber reinforced materials. The weight savings achieved with carbon fiber reinforcement stems from the fact that carbon has a lower density than glass and produces stronger and stiffer parts at a given thickness.
Weight savings in the auto, transportation, and logistics based industries has been a major focus in order to make more fuel efficient vehicles both for ground and air transport. Weight savings using carbon reinforced composites in vehicle parts has helped these industries achieve meaningful weight savings. However, high quality surface finishes, such as a class-A surfaces in the auto industry that are characterized by a high surface sheen, are generally obtained only with highly tailored resin formulations that contain glass fibers, such as TCA® resins commercially available from Continental Structural Plastics, Inc. used in SMC or RTM, or metals such as aluminum and alloys thereof. Class-A surfaces are generally required for vehicle surface panels: doors, hoods, quarter panels, trunks, roof structures, bumpers, etc., which make up a significant amount of weight in a vehicle.
Thus, there exists a need for a process and design to utilize carbon reinforced parts for vehicle surface panels.